Transmission controlled emission control system

ABSTRACT

A vehicle emission control system includes a hydraulically operated exhaust gas recirculation control valve and a hydraulically operated reaction air control valve for controlling emissions from an internal combustion engine under the control of hydraulic valves in an automatic transmission. A transmission modulator valve produces an output signal related to engine manifold pressure and may be biased by vehicle speed. If the latter is the case, a manifold reference valve differentiates the modulator pressure signal to produce a manifold reference signal that is then applied to an air signal valve that is responsive to transmission clutch pressure and to transmission governor pressure to produce an engine mass flow related output signal that is proportional to manifold pressure and responsive to changes in engine speed produced by operation of the transmission. The output air signal is utilized to operate the hydraulically controlled reactor air control valve and is transmitted through a shuttle-type exhaust gas recirculation signal valve to produce a signal to operate the exhaust gas recirculation valve to cause exhaust gas recirculation in accordance with engine mass flow, the exhaust gas recirculation signal valve includes means responsive to wide open throttle position to terminate the exhaust gas recirculation under this increased load condition.

Unite Chana tats atent [191 1 1 TRANSMISSION CONTROLLED EMllSSlON CONTROL SYSTEM [75] Inventor: Howard E. Chana, Troy, Mich.

[73] Assignee: General Motors Corporation,

Detroit, Mich. [22] Filed: Oct. 5, 1973 [21] Appl. No.: 403,929

[52] US. Cl 74/856, 60/278, 60/290, 74/859, 123/119 A [51] Int. Cl. F02m 25/06 [58] Field of Search 74/843, 856. 859, 857,

156] References Cited UNITED STATES PATENTS 3.086.353 4/1963 Ritlgway 60/290 X 3.397.534 8/1968 Knowles 60/290 3.507.260 4/1970 Walker 123/119 A 3.782.348 1/1974 Linder 123/119 A Primary E.rttminet'Samue1 Scott Assistant Examiner-John Reep Attorney, Agent, or Ft'rm-J. C. Evans [57] ABSTRACT A vehicle emission control system includes a hydraulically operated exhaust gas recirculation control valve and a hydraulically operated reaction air control valve for controlling emissions from an internal combustion engine under the control of hydraulic valves in an automatic transmission. A transmission modulator valve produces an output signal related to engine manifold pressure and may be biased by vehicle speed. If the latter is the case, a manifold reference valve differentiates the modulator pressure signal to produce a manifold reference signal that is then applied to an air signal valve that is responsive to transmission clutch pressure and to transmission governor pressure to produce an engine mass flow related output signal that is proportional to manifold pressure and responsive to changes in engine speed produced by operation of the transmission. The output air signal is utilized to operate the hydraulically controlled reactor air control valve and is transmitted through a shuttle-type exhaust gas recirculation signal valve to produce a signal to operate the exhaust gas recirculation valve to cause exhaust gas recirculation in accordance with engine mass flow, the exhaust gas recirculation signal valve includes means responsive to wide open throttle position to terminate the exhaust gas recirculation under this increased load condition.

4 Claims, 11 Drawing Figures PATENTED HAR 5 SHEET 1 8? 3 TRANSMISSION CONTROLLED EMISSION CONTROL SYSTEM This invention relates to emission control systems for internal combustion engines and more particularly to such systems including regulator valves for proportioning exhaust gas recirculation and/or reactor air flow in accordance with engine operating conditions.

It has been proposed to direct reactor air into the exhaust manifold of vehicles to minimize hydrocarbon and CO emissions. In such systems, it is necessary to closely control the amount of reactor air added to the exhaust manifold to assure that there will be sufficient air to oxidize hydrocarbons and CO remaining in the exhaust gas. The control should prevent excessive air flow that might quench the exhaust gas below the reaction temperature. In present systems, this control is established by operating an air injection pump in accordance with engine speed. Such systems include a diverter and a blow-off valve to limit reactor air flow to the exhaust manifold.

Another emission control method is to recirculate exhaust gas from the exhaust manifold of the vehicle to the induction passage thereof. Present systems include a vacuum operated control valve regulated by vacuum signals at a carburetor port. Such systems are difficult to control under very light throttle low speed operations and do not reflect mass flow of air and fuel to the engine under all operating conditions.

An object of the present invention is to improve control ofexhaust gas for recirculation and reactor air flow to exhaust manifolds by provision by hydraulic components in a transmission including valve components responsive to car speed, gear ratio, and intake manifold pressure to compute a signal proportional to enging mass flow for controlling exhaust gas recirculation and reactor air valve means to supply exhaust gas recirculation and reaction air in accordance with engine mass flow.

Yet another object of the present invention is to provide an improved emission control system utiliziing existing transmission valve components of the type sensing line pressure of a hydraulic supply in the transmission and a speed responsive governor pressure produced therein and further responsive to intake manifold pressure of a vehicle to produce a modulated pressure signal for use in the transmission and wherein further valve means are included in the transmission to differentiate the modulated pressure signal to produce a hydraulic signal of a magnitude which will reflect intake mass flow conditions in the vehicle under a wide range of engine operating conditions including changes in speed, load and throttle positions to regulate exhaust gas recirculation and direct exhaust gas into the intake manifold in accordance with mass flow and terminating it upon wide open throttle operations and furthermore to produce an air signal which is proportional to speed for producing an air flow to an exhaust manifold reactor which is in accordance with engine mass flow conditions.

Yet another object of the present invention is to improve the control of exhaust gas recirculation between an exhaust manifold of an internal combustion engine and an induction passage therein by the provision of a hydraulic actuator having a signal port thereto and a contoured exhaust gas recirculation control valve interposed between an inlet from the exhaust manifold and an outlet to the induction passage for metering flow therebetween in accordance with the position of the contoured valve, the hydraulic actuator signal port being coupled to a transmission control including modulator valve means for producing an output signal related to intake manifold pressure and vehicle speed and further including valve means for differentiating the modulator output signal to produce a control signal proportional solely to manifold pressure and thereafter using the manifold pressure signal. to regulate the hydraulic actuation of the exhaust gas recirculation control valve to produce an exhaust gas recirculation reflecting mass flow to the engine and including means for cutting off exhaust gas recirculation on wide open throttle operation.

Still another object of the present invention is to improve the control of reactor air flow from an air supply to a reactor chamber in an exhaust manifold by the provision of a hydraulically controlled reactor air control valve having an inlet connected to a source of air and an outlet connected to a reactor passage to an exhaust manifold, the air reactor control valve including a hydraulic actuator having a signal port, an automatic transmission including valve means therein for producing a hydraulic output signal proportional to intake manifold pressure and varying :in accordance with speed shifts in the transmission to provide a signal that increases in accordance with engine speed to reflect mass flow conditions to the engine; the signal being directed to the hydraulic actuator for producing a flow of reactor air into the exhaust manifold reflecting mass flow conditions in the engine thereby to improve the reaction of combustion products in the exhaust manifold.

Further objects and advantages of the present invention will be apparent from the following description and drawings for a preferred embodiment, in which:

FIG. 1 is a top plan view of a V-8 engine intake manifold containing induction passages and an exhaust crossover passage, together with a carburetor spacer plate containing an exhaust gas recirculation passage and carrying an exhaust gas recirculation control valve assembly;

FIG. 2 is a transverse sectional view taken generally along the line 2-2 of FIG. 1, showing the induction passage plenums and the exhaust crossover passage in the manifold and the inlet to the exhaust gas recirculation passage in the spacer plate, along with a sectional view of a hydraulically operated exhaust gas recirculation valve and a schematic rendering of a transmission control for the recirculation valve;

FIG. 3 is a sectional view of an air reactor system including an air control valve and an engine exhaust valve modified to include a reactor air supply passage for air flow from the control valve to an exhaust manifold reactor;

FIG. 4 is a fragmentary sectional view of a manifold reference control valve in the transmission of FIG. 2;

FIG. 5 is a fragmentary sectional view of an air signal control valve in the transmission of FIG. 2;

FIG. 6 is a fragmentary sectional view of an exhaust gas recirculation signal valve in the transmission of FIG. 2;

FIG. 7 is a graph showing the relationship between an air signal from the valve of FIG. 5 and engine speed;

FIG. 8 is a fragmentary sectional view of a modified valve for producing an exhaust gas recirculation control signal;

FIG. 9 is a fragmentary sectional view of a further embodiment of a transmission control valve for producing an exhaust gas recirculation control signal;

FIG. 10 is a graph showing the operating characteristics of the valve in FIG. 8; and

FIG. 11 is a graph showing the operating characteristics of the control valve in FIG. 9.

Referring first to FIGS. 1 and 2, an intake manifold 10 has a pair of vertical primary riser bores 12 and 14 and a pair of vertical secondary riser bores 16 and 18. Riser bores 12 and 16 open to an upper horizontal plenum 20 connected forwardly (leftwardly as viewed in FIG. 1) to a pair of transverse runners 22 and 24 and connected rearwardly (rightwardly as viewed in FIG. I) to another pair of transverse runners 26 and 28. Similarly, riser bores 14 and 18 open to a lower horizontal plenum 30 connected forwardly to a pair of transverse runners 32 and 34 and rearwardly to another pair of transverse runners 36 and 38.

An exhaust crossover passage 40 extends transversely from the lift-hand side of manifold 10 beneath plenums 20 and 30 and receives a portion of the exhaust gases discharged from the engine combustion chambers.

An insert plate 42 is secured on manifold 10 and has primary riser bores 44 and 46 and secondary riser bores 48 and 50 which meet, respectively, riser bores 12, 14, l6. 18 of manifold 10.

A carburetor 52 is secured on insert plate 42 and has primary throttle bores 54 and 56 which meet, respectively, primary riser bores 44 and 46 of insert plate 42. Carburetor 52 also has secondary throttle bores (not shown) which meet secondary riser bores 48 and 50 of insert plate 42.

A bore 58 in manifold 10 leads upwardly from exhaust crossover passage 40 to the first portion 60 of an exhaust recirculation passage formed in insert plate 42. The first portion 60 of the exhaust recirculation passage leads through a control valve 62 to a second portion 64 of the exhaust recirculation passage as best shown in FIG. 1. This second portion 64 divides into a pair of branches 66 and 68 which lead to the primary riser bores 44 and 46 in insert plate 42.

It should be appreciated that both portions 60 and 64 of the exhaust recirculation passage may be integrated in manifold 10 rather than in separate insert plate 42.

The control valve 62 serves as an exhaust gas recirculation control valve. It has a hydraulic actuator 70 with an upper housing 71 formed as an inverted cup with a peripheral flange 72 thereon secured to an upper flange 74 on a second housing member 76 with a side port 78 therein in communication with atmosphere. A flexible bellophragm element 80 has a peripheral upper flange thereon secured to the flanges 72, 74 is sealing relationship therewith to define a variable volume hydraulic chamber 82 with an inlet signal port 84 thereto formed on the upper housing member 71.

A piston 86 supports the bellophragm 80 and is secured thereto by means of a nut 88 secured on the upper threaded end 90 of a depending piston rod 92. A second nut 94 is engaged with the under-surface of the piston 86 for securely fastening the piston with respect to the bellophragm and to the upper end of the piston rod 92. Hydraulic forces acting on the effective area of the bellophragm 80 and piston 86 are balanced by a bias spring 96 of selected rate and load having the upper end thereof in engagement with the lower surface of the piston 86 and the opposite end thereof supported on the upper end of a valve housing 98 separated into an inlet chamber 100 and a discharge chamber 102 by a divider wall 104. The divider wall 104 has an orifice 106 therein communicating an inlet port 108 on the housing 98 with an outlet port 110 therein. The inlet port 108 is in communication with the first portion 60 of the exhaust gas recirculation passage and the outlet port 110 therein is in communication with the second portion 64 thereof to complete an exhaust gas recirculation path from the exhaust crossover passage 40 to the branches 66 and 68 which lead to the primary riser bores 44 and 46 in the insert plate 42. In accordance with certain principles of the present'invention a hydraulic signal is directed into the chamber 82 to produce a force on the piston rod 92 of a magnitude causing other forces acting thereon to be negligible.

A valve element 112 is secured on the end of the piston rod 92. It includes a contoured outer surface 114 thereon located within the orifice 106 to produce proper exhaust gas recirculation flow at various hydraulic pressures in the chamber 82. When the valve element 1 12 is positioned in a spring return position by the bias spring 96, it forms a positive seal on the orifice 106. The length of piston travel can be relatively long, producing a long stroke capability in the control valve 62 to give precise control of flow from the inlet 108 to the outlet 110 over a wide range of hydraulic pressure directed into the chamber 82.

In addition to the control valve 62, the emission control system of the present invention includes a reactor air control valve 116 which has a hydraulic actuator 118 having the same configuration as the hydraulic actuator 70 in the case of the exhaust gas recirculation valve 62. In FIG. 3 only a portion of a bottom housing member 120 is shown along with a portion of a bias spring 122 and a portion of a piston rod 124 which is secured to a support piston and bellophragm element (not shown) formiing part ofa variable volume hydraulic control chamber with a signal port thereto as in the case of the exhaust gas recirculation control valve 62. The reactor control valve 116 includes a valve housing 126 with an inlet chamber 128 and an outlet chamber 130 separated by a divider wall 132 having an orifice 134 therein with a contoured valve plunger 135 on the end of rod 124. The orifice 134 serves to communicate an inlet port 136 on the valve housing 126 leading to the inlet chamber 128 with an outlet port 138 on housing 126 which communicates with the discharge chamber 130.

An air supply pump 140 has an outlet therefrom connected by means of a conduit 142 with the inlet 136 and an outlet conduit 144 connects the outlet port 138 with an air reactor passage 146 through an exhaust manifold 148. The reactor passage 146 communicates w th a manifold bore 150 communicating with an exhaust passage 152 leading from an exhaust port 154 closed by an exhaust valve 156. The exhaust valve 156 includes a stem 1S8 thereon slidably supported by a port 154 and passage 152. In the illustrated arrangement the air supply from the pump 140 is discharged through the reactor passage 146 in the exhaust manifold as close to the exhaust valve as possible. In some cases, it is desirable to control the air injection at each cylinder to periods only when the exhaust valve is opened. This control is provided by the relationship between the bore 150 and the cylindrical extension 161 on the valve 156.

In the illustrated arrangement, the valve 116 further includes an air pump pressure maximum blow-off valve 162 located in a housing 163. It includes a valve element 164 maintained in sealed engagement with the seat of an orifice 166 by means of a bias spring 168. When low air flows are required under close throttle conditions or light engine load, excess air from pump 140 will discharge through the blow-off valve orifice 166, thence through an outlet 170 in the housing 163 to atmosphere or the air pump inlet.

In accordance with certain principles of the present invention both the reactor air control valve 116 and the exhaust gas recirculation valve 62 are under the control of transmission valve means. One advantage to this is that the transmission includes all inputs to reasonalby determine engine mass flow. Secondly, it can produce signals of sizable magnitude. Third, the transmission control is capable of tapering signals for very light load, road load, and slow speed operation.

In FIG. 2 a transmission 172 is illustrated. It is a standard hydraulic transmission of the type including a fluid supply pump therein for producing transmission line pressure for regulating the operation of control valves within the transmission and an exhaust pressure system in communication with a hydraulic sump. The transmission further includes a modulator valve 174 and a governor 176 which produces a pressure signal in accordance with vehicle speed.

The modulator valve 174 includes a valve member 177 including a piston 178 and plurality of spaced lands 180 and 182, with the lands 180, 182 having a diameter differing from that of piston 178. Face 181 of the piston 178 is vented at port 183 and piston 178 is acted upon by a force generated by manifold pressure from line 185 operating on a diaphragm assembly 187 with a movable pin 189 which biases the valve member 177 against pressures acting on land 182. The land 182 is located in a bore 184 forming a chamber 186 below the land 182. A passage 188 through the land 182 communicates chamber 186 with either a line pressure passage 190 or an exhaust passage 192 in valve 174 in accordance with the position of the valve 177 therein. The valve further includes a governor pressure passage 194 that is communicated with an output signal from the governor 176 through suitable conduit means 196.

By virtue of the aforedescribed arrangement, the valve member 177 will be shifted in response to changes in intake manifold pressure against line pressure and governor pressure to produce an output signal through a modulator pressure passage 198 which is related to engine manifold pressure and vehicle speed by a relationship set forth by the following equation:

The terms in the aforedescribed equation are as set forth below.

P,, modulator valve pressure signal F= operating force on piston l7i8produced by manifold pressure I A, cross-sectional area of lands and 182 p governor pressure signal A cross-sectional area of piston 178 The modulator valve 174, previously described, is found in automatic transmissions of the type shown in U.S. Pat. No. 3,321,056, issued May 23, 1967, to F. J. Winchell, et al. The governor signal produced for use in the aforedescribed system is more particularly set forth in US. Pat. No. 2,762,384, issued Sep. 11, 1956, to M. S. Rosenburger.

The transmission control system further includes a manifold reference valve 200 which is illustrated in FIG. 4. It takes the transmission modulator pressure from passage 198 and converts it back to a reference pressure which is proportional to manifold pressure. More particularly, the valve 200 includes a valve member 202 having lands 204, 206 thereon slidably supported in a first bore 208. A second land 209 on the valve 202 is supportingly received in bore 210 having an area less than the area of lands 204, 206. The land 204 has a passage 212 therethrough communicating a chamber 214 with a line pressure passage 216 or an exhaust passage 220 dependent on the position of valve 202. An output passage 218 therefore has a pressure signal directed to it that is proportional to manifold pressure. A governor pressure passage 222 directs governor pressure to the backside of the land 206 and against the foreside of the land 209 which has the opposite face thereon in communication with a modulator pressure passage 224 which is in communication with the passage 198 from the modulator pressure valve 174. The selected valve diameters can be modified to meet the demands of the transmission control and engine emission system.

The valve 200 thereby is controlled in accordance with the governor pressure and modulator pressure to selectively control flow from line: pressure and to exhaust to establish the pressure reference signal at passageway 218 in accordance with the following equations:

or simplifying with (l) 3 P218 zoe In order to produce a hydraulic signal that accurately reflects mass flow conditions into the induction passages of an internal combustion engine, it is necessary to further incorporate a signal that reflects engine speed.

Accordingly, in the control system of the present invention a signal valve 226 is included having a valve element 228 therein including spaced apart lands 230, 232 located in a valve bore 234. The valve 228 is coupled by an interconnecting pin 236 to another valve 237 having a plurality of lands 238, 240, 242 with progressively decreasing diameters operating in bores 244, 246, 248, respectively.

The land 230 has one end thereof located in a pressure chamber 250 connected to transmission governor pressure. It controls communication between an exhaust passageway 252 and reference signal pressure passage 258 which is in communication with the output passage 218 from valve 200. An output signal is generated in passageway 254. The land 232 has an end-toend passage 256 therethrough communicating passage 258 with chamber 260.

In order to produce an output signal in passageway 254 which further reflects engine speed conditions, the signal valve 226 further includes a passage 262 located between the lands 238 and 240 which is in communication with a transmission pressure having a direct clutch pressure therein reflecting a pressure condition P in a transmission of type shown in U.S. Pat. No. 3,321,056 to Winchell, et al., which occurs at an upshift between secondand third speed ranges. Further, the valve includes a passage 264 therein in communication with a transmission pressure reflecting an intermediate clutch pressure condition 1 which occurs after an upshift from first to second speed ranges. The valve further includes a passage or chamber 266 therein in communication with a passage 268 to the exhaust side of the hydraulic system of a transmission. A further exhaust passage 270 communicates with the end of the land 238 opposite the passage 262.

By virtue of the aforedescribed valve assembly 226, a signal pressure is produced in passageway 254 designated P that can be utilized to control both the exhaust gas recirculation valve 62 and the air reactor control valve 116. The output air pressure P is a reflection of the governor pressure limited by the reference manifold pressure from valve 200 and reduced by transmission speed signals P and P The output air signal is thereby established by the following operating equation which neglects the area of the interconnecting pen 236 and is derived on the basis of the pressure in chamber 266 being exhausted.

4 254 250 P262(A238 240 M230 2s4( 240 242 2a0) where P cannot exceed P For a near wide open throttle acceleration, the air signal pressure will have characteristics related to engine RPM as determined from vehicle speed as set forth in the graph of FIG. 7. The curve 272 therein reflects engine RPM speed produced by upshifting ofa hydraulic transmission and the resultant pressure reference signal P produced at the outlet passage 254 in the valve 226 is illustrated by curve 274.

As will be noted, the pressure signal P. is a function of engine speed and yet will be limited by manifold pressure; that is, for low manifold pressures it will be limited to a low value and at intermediate manifold pressures it will be limited to a higher value.

The air signal pressure is also zero at zero vehicle speed increasing at a rapid rate as vehicle speed is increased. The air output signal is suitable for use to actuate the control valve 116 and will be directly fed to the hydraulic actuator 118 thereon which is of the type specifically set forth at 70 for actuating the exhaust gas recirculation valve 62.

Thus, as engine speed increases the valve 226 will further incorporate a reflection of manifold pressure conditions to produce a resultant signal reflecting mass flow into the engine. As mass flow increases, the hydraulic signal will increase to a proportional level to produce a downward pressure on the piston rod 124 in the valve 116 to cause the contoured valve plunger 135 thereon to move away from the walls of the orifice 134 thereby to allow a greater amount of reactor air to flow from the pump 140 thence through the inlet port 136, inlet chamber 128, through orifice 134, outlet chamber and outlet port 138 thence through conduit 144 and reactor passage 146 to the bore 150 where the controlled amount of air will react with the additional combustion products produced by the then present mass flow and react more effectively with the excess hydrocarbon and CO emissions to improve oxidation of these components, thereby to improve the quality of exhaust gas emissions from the vehicle. The amount of reactor air will be closely proportioned to engine mass flow to produce optimum results.

The long stroke of the plunger valve element and the shape thereon will give precise control of air flow over a wide range of control pressure produced by the valve 226 in accordance with transmission operation that reflects changes in intake manifold pressure and changes in engine speed. The piston rod 124 has a stop position just prior to the point that the tapered valve plunger 135 is seated against the walls of the orifice 134 to provide a required minimum air flow for idle conditions. This could also be provided by a by-pass orifice in parallel to 134. As was stated above, under conditions where air pump flow is greater than that needed, excess air will discharge through the blow-off valve 162. This system takes the place of vacuum operator diverter and blow-off valves in air reactor systems presently in use.

The signal produced at passage 254 of valve 226 exists at wide open throttle and is therefore not completely desirable for exhaust gas recirculation control.

Accordingly, the system as shown in FIG. 6 further includes an exhaust gas recirculation signal valve 276 which includes a shuttle valve 278 therein including spaced apart land portions 280, 282 slidably received in a bore 284.

One end of the shuttle valve 278 is in communication with an exhaust passage 286. A bias spring 288 in bore 284 engages the exhaust end of the shuttle valve 278 around a stop pin 290 thereon. The opposite end of the shuttle valve is located in a passage 292 in communication with a detent pressure system in a transmission of the type shown in U.S. Pat. No. 3,321,056 to Winchell, et al. This system will be pressurized in accordance with wide open throttle conditions to produce a pressure signal on the shuttle valve 278 that will cause it to compress spring 288 and move the lands 280, 282 in a direction to block an input signal passage 294 in communication with the outlet from the signal passage 254 of valve 226 and will communicate an exhaust gas recirculation pressure signal passage 296 therein with an exhaust passage 298 whereby the manifold and engine speed responsive signal in passage 254 is blocked from the output signal passage 296 in valve 276 at wide open throttle conditions.

Under other throttle positions the valve 278 serves as a shuttle valve to direct the signal from the signal valve 226 to the signal port 84 of the hydraulic actuator 74 of the exhaust gas recirculation valve. As the signal increases as shown in FIG. 7, the controured plunger valve 114 will move downwardly with respect to the seat defined by the orifice 106 to cause increasing exhaust gas recirculation between the exhaust manifold of an internal combustion engine and the induction passages therein in accordance with increases in mass flow to the induction passages of the vehicle thereby to produce an effective control of N0 The operation of the exhaust gas recirculation signal valve 276, however, will terminate the signal to the hydraulic actuator 74 of valve 62 at wide open throttle conditions to terminate exhaust gas recirculation.

The aforedescribed system illustrated in FIGS. 1 through 7 is capable of use for control of an air reactor system or an exhaust gas recirculation taken together or to operate them independently.

The aforedescribed system, in addition, accurately reflects mass flow conditions in the engine to control both exhaust gas recirculation and reactor air in accordance therewith. Furthermore, it will have no signal under idle conditions. The signal as shown in FIG. 7 increases rapidly as vehicle speed increases from zero, the increase being related both to intake manifold pressure conditions and engine speed conditions.

The signal at output passage 254, by virtue of the intake manifold pressure control, is limited by manifold depression. Design of valve 226 can be such that there will be no signal from the valve 226 under coast conditions and there will be a maximum signal therefrom at maximum inlet manifold pressures and high engine speeds. Furthermore, the signal from the valve 226 is limited by manifold pressure under part throttle conditions.

The signal is controlled by engine speed as computed from propeller shaft speed and the transmission operating condition as determined by the pressure conditions at passages 262 and 264 in valve 226. Furthermore, by virtue of the arrangement in FIG. 6, the output signal to the exhaust recirculation control valve can be zero for wide open throttle operations to match the system to desirable exhaust gas recirculation control.

The above features when combined will give best drivability and minimum emissions from the vehicle. They can be accomplished by minor calibration of existing transmission control such as a modulator valve 174 along with hydraulic control valves of the type set forth in FIGS. 4 through 6. Valve system 226 can be used for exhaust gas recirculation control if transmission detent pressure is applied to port 268 and chamber 266. Detent pressure will force the valve system to the left under wide open throttle operation exhausting sig nal pressure at port 254.

While hydraulic signals and hydraulic valve actuators are illustrated, the control valves 62, 116 could also be operated by vacuum controllers that are responsive to hydraulic output signals of the type type above set forth.

In cases where only exhaust gas recirculation is controlled, other methods utilizing transmission signals can be used to develope a positive hydraulic signal which can be directed to the signal port 84 of the hydraulic actuator 70 for exhaust gas recirculation control valve 62, the signal being a combination of transmission governor pressure P modulator pressure P and detent pressure P combined to give a resultant pressure P to operate the exhaust gas recirculation control valve to produe increasing exhaust gas recirculation in response to vehicle operating speed conditions but limited by modulator pressure and providing a cut-off of the exhaust gas recirculation signal when the detent pressure exists under wide open throttle conditions.

With reference to FIG. 8, a control valve 300 for this purpose is illustrated including a valve element 302 having lands 304, 306 thereon slidably supported within at bore 305. The valve element 302 includes a stop pin 307 thereon selectively engaged by a cupshaped piston 308 slidably supported in a large diameter bore 310. A bias spring 312 holds the piston 308 in a stop position as shown in FIG. 8 until the vehicle is operated at wide open throttle positions at which time a pressusre is produced in a detent pressure passage 314 to move piston 308 against the bias spring 312 until it engages the pin 307 to shift the valve element 302 to the right as viewed in FIG. 8. Under these conditions, the land 306 communicates an exhaust recirculation control pressure signal passage 316 with an exhaust passage 318 to produce a zero emission control signal under wide open throttle conditions thereby to terminate exhaust gas recirculation under this phase of vehicle operation.

For other phases of operation, the valve element 302 is positioned by governor pressure P, in passaage 320 and a pressure signal P,,, in passage 322 of the type developed by the modulator pressure valve 174 which includes a governor pressure component. The combination of these signals will act on the areas of lands 304, 306 to selectively position the land 304 with respect to the modulator pressure passage 322 to produce a controlled signal in the passage 316 which reflects intake manifold pressure but is controlled by governor pressure. A passage 324 through land 304 between the ends thereof relieves a chamber 326 on the closed end of the bore 305.

An exhaust passage 328 communicates with the bore 310 to permit 'movement of the piston 308 against the pin 307 during wide open throttle operation. Accordingly, the output pressure signal 316 reflects changes in engind load as manifested by changes in intake manifold pressure engine to produce a control of exhaust gas recirculation from the exhaust of an internal combustion engine to the induction passages thereof thereby to control N0 emissions.

The graph in FIG. 10 shows a plurality of curves 330 through 338 representing the modulated pressure signal produced by the transmission modulator valve 174 for various throttle openings. The curve 340 shows the governor pressure signal produced upon increasing output speed and the resultant dotted line extensions of the curves 330 through 338 represent the resultant emission pressure signal produced by the valve 300. It will be seen that as the throttle opening increases from curve 338 to curve 330, the modulator pressure will increase and the governor pressure will increase in accordance with output RPM. The resultant emissions pressure signal will increase in a like manner to produce greater exhaust gas recirculation on increases in load as reflected by changes in intake manifold pressure.

Another embodiment of the invention is illustrated in FIGS. 9 and 11 to produce a resultant pressure P for exhaust gas recirculation control. In this arrangement, a signal valve 342 utilizes a combination of transmission governor pressure P modulator pressure P and detent pressure P combined to give a resultant pressure P, for exhaust gas recirculation control. In this valve, a valve element 344 includes a land 346 extending through a bore 348 into an exhaust chamber 350. The valve element 344 includes a pair of spaced apart lands 352, 354 on the opposite end thereof, one of which is acted on by governor pressure P, in passage 356 and the other ofwhich controls flow through an exhaust passage 358 and an output signal pressure passage 360. A modulator pressure passage 362 receives the signal from the modulator valve of a transmission and is under the control of the land 346. The land 346 includes a stop pin 363 thereon extending into a bore 364 which slidably receives a cup-shaped piston 366 having one end thereof located in a detent pressure passage 367. A pair of bias springs 368, 369 located within the bore 364 each have one end thereof in engagement with the piston 366. Spring 368 has a predetermined rate and load to establish the end points for the control signal P at passage 360. The opposite end of the spring 369 engages the wall of the valve to maintain the piston 366 in its leftward position as seen in FIG. 9 until detent pressure is produced in passage 367 on the occurrence of wide open throttle operation.

The spring 368 reacts against governor pressure in passage 356 operating on land 354 to position the lands 344, 352 with respect to the passages 362 and 358 to control the pressure output in passage 360. As shown in FIG. 11, valve control of FIG. 10 includes a plurality of modulator pressure lines 370 shown in solid line increasing in pressure for different throttle positions. It further includes a governor pressure curve 372 which increases upon increased output shaft RPM. The coil spring 368 biases the valve 344 against the governor pressure in passage 356 until a pressure P,, occurs so that there will be no output signal. At this point, the valve 344 will be shifted by an increase in governor pressure to produce an output signal which is represented for different modulator pressure lines 370 by the output signal lines 374 in FIG. 11.

In the valve of FIG. 9 when the governor pressure reaches a pressure P the valve 344 will be shifted completely to the left to once again coommunicate the signal line or passage 360 with exhaust passage 358. As was the case in the first embodiment, on the occurrence of a detent pressure in passage 367, the piston 366 will move to the right to engage the pin 363 to shift the valve 344 into the solid line position as shown in FIG. 9 to communicate the signal passage 360 with the exhaust passage 358 to terminate the exhaust gas recirculation signal under all P, pressure conditions.

While the embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

I. An exhaust gas recirculation control system for use on an internal combustion engine having an induction passage for air flow to the engine, an exhaust passage for exhaust gas flow from the engine and a recirculation passage having a first portion extending from said exhaust passage and a second portion extending to said induction passage comprising: exhaust gas recirculation control valve means including an inlet connected to the first portion of the recirculation passage and an outlet connected to the second portion of the recirculation passage, means forming an orifice between the inlet and outlet, valve means located within the orifice including a contoured wall portion thereon movable with respect to the walls of the orifice, a valve actuator including a variable volume hydraulic chamber having a signal port thereto, an automatic transmission including a hydraulic supply and a speed responsive governor means for producing a hydraulic signal related to vehicle speed, modulator valve means in said transmission including means sensing engine induction passage pressure and said governor signal for producing an output signal related to induction passage pressure and speed,

and control valve means including means responsive to said governor pressure and said modulator valve output signal to produce an exhaust gas recirculation control signal responsive to induction passage pressure, means for directing said exhaust gas recirculation control signal to said signal port of said actuator means for positioning said valve means with respect to said orifice to control exhaust gas recirculation from the exhaust passage to the induction passage in accordance with pressure in the induction passage.

2. An exhaust gas recirculation control system for use on an internal combustion engine having an induction passage for air flow to the engine, an exhaust passage for exhaust gas flow from the engine modulator a recirculation passage having a first portion extending from said exhaust passage and a second portion extending to said induction passage comprising: transmission means including hydraulic supply means for producing a line pressure and a speed responsive governor means for producing a first hydraulic control signal related to vehicle speed, modulator valve means in said transmission including means for sensing intake manifold pressure and said first governor hydraulic control signal and means for producing an output signal related to intake manifold pressure and vehicle speed, control valve means including means for sensing said modulator output signal, line pressure and the first hydraulic control signal to produce a modulator reference output signal proportional solely to manifold pressure, means responsive to said modulator reference output signal to produce a second hydraulic control signal reflecting mass fiow of air-fuel into the induction passage, an exhaust gas recirculation having an inlet connected to the first portion of the recirculation passage and an outlet connected to the second portion of the recirculation passage, means forming an orifice between said inlet and outlet, a valve element located within said orifice having a contoured wall thereon movable relative to the walls of said orifice to vary exhaust gas recirculation flow between the exhaust passage and the induction passage, means for actuating said valve including a signal port, means for directing said second hydraulic control signal to said signal port, said actuator means positioning said valve in accordance with the pressure level of said second hydraulic signal to vary exhaust gas recirculation in accordance with mass flow through the induction passage of the internal combustion engine.

3. An emission control system for use on an internal combustion engine having an intake manifold for air flow to the engine and an exhaust passage for exhaust gas flow from the engine, an exhaust valve in communication with said exhaust passageway, said exhaust valve having an air injection port therein, means for supplying air to said air injection port including a pump and air control valve means having an inlet connected to said pump and an outlet connected to said air injection port, said air control valve means including a first valve element having a contoured surface, a first orifice surrounding said contoured surface located between said inlet and outlet, actuator means for positioning said first valve element with respect to said orifice for varying air flow between the pump and the air injection port, an exhaust gas recirculation control valve including an inlet and an outlet, means forming a second orifice between said inlet and outlet, a second valve element located within said second orifice including a contoured surface thereon movable with respect to said second orifice, means for positioning said second valve element with respect to said second orifice including a hydraulic control chamber having a signal port thereto, said inlet of said exhaust gas recirculation control valve connected to the exhaust passage, the outlet of said exhaust gas recirculation control valve connected to the intake manifold of the internal combusiton engine, a transmission including hydraulic supply means for producing a line signal and a speed responsive governor means for producing a hydraulic signal related to vehicle speed as well as a detent valve for producing a detent pressure signal in accordance with wide open throttle positions, said transmission means including a modulator valve sensing intake manifold pressure and said governor output signal for producing an output signal related to intake manifold pressure and speed, a manifold reference valve including means for sensing the output from said modulator valve, line pressure and the output signal from said governor to produce a reference signal proportional solely to manifold pressure, a reactor air signal valve including an inlet connected to the reference signal from said manifold reference valve and means for sensing the governor output pressure and transmission clutch pressures to produce an output air signal which increases in accordance with engine speed, means for directing said output air signal to said air control valve means for regulating reactor air in ac cordance with mass flow to the engine, and exhaust gas recirculation signal valve means including an input port for receiving the output air signal from said air signal valve and an output port for directing said output air signal to said exhaust gas recirculation valve signal port, said last mentioned signal valve means including means responsive to the detent pressure signal for cutting off said output air signal therefrom in response to transmission detent operation at wide open throttle positions.

4. A system for controlling reaction air flow from an air pump to an exhaust manifold reactor of an engine comprising: a transmission including hydraulic supply means for producing a line pressure signal, means producing a governor pressure signal related to vehicle speed and means for producing a detent pressure in ac cordance with throttle operation beyond a wide open throttle position, a transmission modulator valve including means for sensing vehicle intake manifold pressure and means for sensing line pressure and governor pressure to produce a modulator output pressure signal, manifold reference valve means including an inlet port connected to the modulator output signal and means for sensing line pressure and governor pressure and operative to produce an output reference signal proportional to the intake manifold pressure, air signal valve means including an input passage, an output passage and a valve element with a first land portion interposed between the input passage connected to the output reference signal and the output passage, means directing governor pressure against one end of said valve element, a valve element actuator including a plurality of lands selectively pressured by direct clutch pressured from the transmission for positioning said valve element so as to modulate communication beyween the input and th output passages to produce an air signal pressure therefrom in accordance with vehicle speed and manifold pressure, a reactor air supply pump, an air pressure control valve including an inlet connected to said reactor air supply pump and an outlet, reactor air passage means for directing reactor air into an exhaust manifold for reaction with combusiton products, means for communicating said air pressure control valve outlet with said reactor air passage means, actuator means for said air pressure control valve to control communication between the inlet and outlet therefrom including a signal port, and means for directing said air pressure signal to said actuator means signal port to control said air pressure control valve in accordance with engine speed and intake manifold pressure to increase reactor air in accordance With mass flow to the engine for improving combustion of exhaust gases within said exhaust manifold.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,868,868

DATED March 4, 1975 INV N O 1 Howard E. Chana It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Patent Column Line 1 52 change "a" t0 the 9 48 "type" appears twice;

delete one occurrence of the word "type" 10 34 after "pressure, delete "engine" and insert thereby l2 14 after engine" delete "modulator" and insert and 12 33 after "recirculation" insert valve Signed. and sealed this 24th. day of June 19-75.

SEAL) Attest:

C. l"iARSHALL DANN RUTH C. MASON Commissioner of Patents attesting Officer and Trademarks 

1. An exhaust gas recirculation control system for use on an internal combustion engine having an induction passage for air flow to the engine, an exhaust passage for exhaust gas flow from the engine and a recirculation passage having a first portion extending from said exhaust passage and a second portion extending to said induction passage comprising: exhaust gas recirculation control valve means including an inlet connected to the first portion of the recirculation passage and an outlet connected to the second portion of the recirculation passage, means forming an orifice between the inlet and outlet, valve means located within the orifice including a contoured wall portion thereon movable with respect to the walls of the orifice, a valve actuator including a variable volume hydraulic chamber having a signal port thereto, an automatic transmission including a hydraulic supply and a speed responsive governor means for producing a hydraulic signal related to vehicle speed, modulator valve means in said transmission including means sensing engine induction passage pressure and said governor signal for producing an output signal related to induction passage pressure and speed, and control valve Means including means responsive to said governor pressure and said modulator valve output signal to produce an exhaust gas recirculation control signal responsive to induction passage pressure, means for directing said exhaust gas recirculation control signal to said signal port of said actuator means for positioning said valve means with respect to said orifice to control exhaust gas recirculation from the exhaust passage to the induction passage in accordance with pressure in the induction passage.
 2. An exhaust gas recirculation control system for use on an internal combustion engine having an induction passage for air flow to the engine, an exhaust passage for exhaust gas flow from the engine modulator a recirculation passage having a first portion extending from said exhaust passage and a second portion extending to said induction passage comprising: transmission means including hydraulic supply means for producing a line pressure and a speed responsive governor means for producing a first hydraulic control signal related to vehicle speed, modulator valve means in said transmission including means for sensing intake manifold pressure and said first governor hydraulic control signal and means for producing an output signal related to intake manifold pressure and vehicle speed, control valve means including means for sensing said modulator output signal, line pressure and the first hydraulic control signal to produce a modulator reference output signal proportional solely to manifold pressure, means responsive to said modulator reference output signal to produce a second hydraulic control signal reflecting mass flow of air-fuel into the induction passage, an exhaust gas recirculation having an inlet connected to the first portion of the recirculation passage and an outlet connected to the second portion of the recirculation passage, means forming an orifice between said inlet and outlet, a valve element located within said orifice having a contoured wall thereon movable relative to the walls of said orifice to vary exhaust gas recirculation flow between the exhaust passage and the induction passage, means for actuating said valve including a signal port, means for directing said second hydraulic control signal to said signal port, said actuator means positioning said valve in accordance with the pressure level of said second hydraulic signal to vary exhaust gas recirculation in accordance with mass flow through the induction passage of the internal combustion engine.
 3. An emission control system for use on an internal combustion engine having an intake manifold for air flow to the engine and an exhaust passage for exhaust gas flow from the engine, an exhaust valve in communication with said exhaust passageway, said exhaust valve having an air injection port therein, means for supplying air to said air injection port including a pump and air control valve means having an inlet connected to said pump and an outlet connected to said air injection port, said air control valve means including a first valve element having a contoured surface, a first orifice surrounding said contoured surface located between said inlet and outlet, actuator means for positioning said first valve element with respect to said orifice for varying air flow between the pump and the air injection port, an exhaust gas recirculation control valve including an inlet and an outlet, means forming a second orifice between said inlet and outlet, a second valve element located within said second orifice including a contoured surface thereon movable with respect to said second orifice, means for positioning said second valve element with respect to said second orifice including a hydraulic control chamber having a signal port thereto, said inlet of said exhaust gas recirculation control valve connected to the exhaust passage, the outlet of said exhaust gas recirculation control valve connected to the intake manifold of the internal combusiton engine, a transmission including hydraulic supply means for Producing a line signal and a speed responsive governor means for producing a hydraulic signal related to vehicle speed as well as a detent valve for producing a detent pressure signal in accordance with wide open throttle positions, said transmission means including a modulator valve sensing intake manifold pressure and said governor output signal for producing an output signal related to intake manifold pressure and speed, a manifold reference valve including means for sensing the output from said modulator valve, line pressure and the output signal from said governor to produce a reference signal proportional solely to manifold pressure, a reactor air signal valve including an inlet connected to the reference signal from said manifold reference valve and means for sensing the governor output pressure and transmission clutch pressures to produce an output air signal which increases in accordance with engine speed, means for directing said output air signal to said air control valve means for regulating reactor air in accordance with mass flow to the engine, and exhaust gas recirculation signal valve means including an input port for receiving the output air signal from said air signal valve and an output port for directing said output air signal to said exhaust gas recirculation valve signal port, said last mentioned signal valve means including means responsive to the detent pressure signal for cutting off said output air signal therefrom in response to transmission detent operation at wide open throttle positions.
 4. A system for controlling reaction air flow from an air pump to an exhaust manifold reactor of an engine comprising: a transmission including hydraulic supply means for producing a line pressure signal, means producing a governor pressure signal related to vehicle speed and means for producing a detent pressure in accordance with throttle operation beyond a wide open throttle position, a transmission modulator valve including means for sensing vehicle intake manifold pressure and means for sensing line pressure and governor pressure to produce a modulator output pressure signal, manifold reference valve means including an inlet port connected to the modulator output signal and means for sensing line pressure and governor pressure and operative to produce an output reference signal proportional to the intake manifold pressure, air signal valve means including an input passage, an output passage and a valve element with a first land portion interposed between the input passage connected to the output reference signal and the output passage, means directing governor pressure against one end of said valve element, a valve element actuator including a plurality of lands selectively pressured by direct clutch pressured from the transmission for positioning said valve element so as to modulate communication beyween the input and th output passages to produce an air signal pressure therefrom in accordance with vehicle speed and manifold pressure, a reactor air supply pump, an air pressure control valve including an inlet connected to said reactor air supply pump and an outlet, reactor air passage means for directing reactor air into an exhaust manifold for reaction with combusiton products, means for communicating said air pressure control valve outlet with said reactor air passage means, actuator means for said air pressure control valve to control communication between the inlet and outlet therefrom including a signal port, and means for directing said air pressure signal to said actuator means signal port to control said air pressure control valve in accordance with engine speed and intake manifold pressure to increase reactor air in accordance with mass flow to the engine for improving combustion of exhaust gases within said exhaust manifold. 